How much does solar heating help? If you have a solar heated pool, how many extra weeks or months of comfortable swimming do you get in a year, and how much did you spend on your system?
Is solar heating worth it?
- Thread starter TomAtlanta
- Start date
1.5-2 months. My pool is only half the size of yours and my 2 panels are right next to the pool, so it does not get much more simple than that, with supplies it cost me roughly $800 diy. You are looking at least double that plus installation costs (dependent on who installs and location of panels). That said outside of the initial investment which you will also have with a traditional heater/gas lines, etc.... it's free heat.
Lots of factors ... like how many panels, what is their exposure to the sun, what is the pools exposure to the sun, do you use a cover.
Last house I paid ~$4000 for solar install. This house I bought 500 sqft of panels on CL and am installing myself for $1200.
I never used a cover and the the panels help tremendously with how comfortable the water is in the shoulder seasons and allow some extenstion. It is so dry here that 80 degree water in 100 degree weather can feel pretty cold.
Last house I paid ~$4000 for solar install. This house I bought 500 sqft of panels on CL and am installing myself for $1200.
I never used a cover and the the panels help tremendously with how comfortable the water is in the shoulder seasons and allow some extenstion. It is so dry here that 80 degree water in 100 degree weather can feel pretty cold.
The table in this post shows the situation for my pool. If you don't have solar panels and don't use a cover, then the water temperature in a white plaster pool will be a little warmer than the average day/night temperature. The actual temperature can be higher or lower than this depending on the evaporation rate since the pool water gets heated during the day but it gets cooled by evaporation both day and night so which one wins out depends mostly on wind and humidity.
Figure that a solar bubble-type cover alone will keep heat in the pool (mostly from preventing evaporation and some from reducing conduction) to have its average temperature be 10-15ºF higher than the average day/night air temperature. A fairly large solar system (85% of pool surface area) in conjunction with a cover will heat the pool to 20-25ºF higher than average or sometimes higher (30ºF) if the solar cover is very well insulated.
For our pool, without a cover where we live the water would be at best in the low-to-mid 70's. With a solar cover, it would get to 80-85ºF or maybe a little higher at peak summer so maybe 3 months (Jul, Aug, Sep), but our pool uses a relatively thin mostly opaque electric safety cover so we don't get the full benefit of a bubble-type cover (hence more gas use in Sep). With the solar system, we are able to get to 88ºF without too much use of gas heat for 2 more months (May, Jun). It also reduces the amount of gas heating in other months (Apr, Oct). So roughly speaking where I live, a cover gives us 3 months and the solar panels give us another 2 months and help reduce gas heating costs in an additional 2 months. With gas supplement, we have an expensive 7 month season from roughly mid-April to mid-November. Most people in our area do more of a 5 month season (May-Sep) while some do a traditional 3+ month season from Memorial Day (end of May) to Labor Day (start of September).
Obviously, the devil is in the details including the target pool water temperature vs. the average day/night air temperature. I've put together a similar chart for you based on Atlanta, GA temperatures and solar insolation.
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
.52..57..65...73..80..86...89..88..82...73..64..54 ... Avg. High Temp
.34..38..44...52..60..68...71..71..65...54..45..37 ... Avg. Low Temp
.44..48..55...63..71..78...81..80..74...64..55..46 ... Average Temp (slightly more weight to daytime temp)
4.2 4.8 4.8 3.4 . 3.7 4.0 5.3 3.9 . 4.5 3.4 4.1 3.9 ... Average monthly rainfall in inches
3.4 4.2 5.1 6.0 . 6.2 6.3 6.1 5.9 . 5.3 4.9 3.8 3.2 ... kWh/m2/day from the sun (30-year average for month; panels facing south tilted at 34-15=19 degrees)
So with your higher average day/night temperatures in the summer, you need less supplemental heating and can easily warm your pool with a solar cover for very warm water in the 3 months of Jun, Jul, Aug and probably be OK for low-to-mid 80's in May and Sep. Solar panels would let you heat the pool without a cover in peak summer (Jun, Jul, Aug) and let you extend the season by a couple of months into May and Sep if you use a cover. It would reduce your gas costs in Mar, Apr and Oct if you still wanted to swim (which you might given your milder temperatures) though it won't save a lot of gas unless your target pool water temperature were lower (below 85ºF). Interestingly, you get more sun in the winter compared to where I live because of your latitude, but you get less sun in the summer because of the rain (which implies cloud cover).
Figure that a solar bubble-type cover alone will keep heat in the pool (mostly from preventing evaporation and some from reducing conduction) to have its average temperature be 10-15ºF higher than the average day/night air temperature. A fairly large solar system (85% of pool surface area) in conjunction with a cover will heat the pool to 20-25ºF higher than average or sometimes higher (30ºF) if the solar cover is very well insulated.
For our pool, without a cover where we live the water would be at best in the low-to-mid 70's. With a solar cover, it would get to 80-85ºF or maybe a little higher at peak summer so maybe 3 months (Jul, Aug, Sep), but our pool uses a relatively thin mostly opaque electric safety cover so we don't get the full benefit of a bubble-type cover (hence more gas use in Sep). With the solar system, we are able to get to 88ºF without too much use of gas heat for 2 more months (May, Jun). It also reduces the amount of gas heating in other months (Apr, Oct). So roughly speaking where I live, a cover gives us 3 months and the solar panels give us another 2 months and help reduce gas heating costs in an additional 2 months. With gas supplement, we have an expensive 7 month season from roughly mid-April to mid-November. Most people in our area do more of a 5 month season (May-Sep) while some do a traditional 3+ month season from Memorial Day (end of May) to Labor Day (start of September).
Obviously, the devil is in the details including the target pool water temperature vs. the average day/night air temperature. I've put together a similar chart for you based on Atlanta, GA temperatures and solar insolation.
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
.52..57..65...73..80..86...89..88..82...73..64..54 ... Avg. High Temp
.34..38..44...52..60..68...71..71..65...54..45..37 ... Avg. Low Temp
.44..48..55...63..71..78...81..80..74...64..55..46 ... Average Temp (slightly more weight to daytime temp)
4.2 4.8 4.8 3.4 . 3.7 4.0 5.3 3.9 . 4.5 3.4 4.1 3.9 ... Average monthly rainfall in inches
3.4 4.2 5.1 6.0 . 6.2 6.3 6.1 5.9 . 5.3 4.9 3.8 3.2 ... kWh/m2/day from the sun (30-year average for month; panels facing south tilted at 34-15=19 degrees)
So with your higher average day/night temperatures in the summer, you need less supplemental heating and can easily warm your pool with a solar cover for very warm water in the 3 months of Jun, Jul, Aug and probably be OK for low-to-mid 80's in May and Sep. Solar panels would let you heat the pool without a cover in peak summer (Jun, Jul, Aug) and let you extend the season by a couple of months into May and Sep if you use a cover. It would reduce your gas costs in Mar, Apr and Oct if you still wanted to swim (which you might given your milder temperatures) though it won't save a lot of gas unless your target pool water temperature were lower (below 85ºF). Interestingly, you get more sun in the winter compared to where I live because of your latitude, but you get less sun in the summer because of the rain (which implies cloud cover).
I had never heard of a solar bubble cover until I read the last post. Maybe I will get one.
I have a lot of leaves. If I put the solar cover on and just take it off when we want to swim, that would keep the leaves out of the water, and it would be much prettier than the big black cover I have now. It looks like I could just pull off the solar cover and pretty easily dump the leaves on the ground near the pool. Is that correct?
I found this place that sells solar bubble covers. Are these pretty good?
http://www.backyardcitypools.com/Solar- ... -16mil.htm
I have a lot of leaves. If I put the solar cover on and just take it off when we want to swim, that would keep the leaves out of the water, and it would be much prettier than the big black cover I have now. It looks like I could just pull off the solar cover and pretty easily dump the leaves on the ground near the pool. Is that correct?
I found this place that sells solar bubble covers. Are these pretty good?
http://www.backyardcitypools.com/Solar- ... -16mil.htm
TomAtlanta said:
For my solar cover, I bought a reel pretty quickly after using it. It was a pain for 1 person to get off, and I always got it pretty dirty in the process. With the reel, it dumps most of the collected leaves right into the water. That being said, it is a lot quicker to get them off the surface with a net than fish them out of the bottom.
Solar panels were $4000 installed plus the cost of me building the solar rack, prob about $800 in material. Since April 1st the water has been over 80 deg. In May, June, July, Aug, Sept, and so far October and the water has been at 85 deg. or more in the afternoon, usually gains about 3 / 4 deg if its sunny and the temp is 75+ deg. I set the thermostat at 86. I did get it to 91 deg once but that was just too hot to enjoy during the day. It will start dropping any time now, last year on October 31st it was 72 deg, my last swim of the year.
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